NEMI Method Summary

Method Summary Information

Method Number: 2340B Media: WATER
Revision: Standard Methods Online
Method Source: Standard Methods
Subcategory: INORGANIC Analytes in this method
Official Name: Hardness in Water by EDTA Titration
Descriptive Name Hardness in Water by EDTA Titration
Source Info: Standard Methods Online is jointly produced by the American Public Health Association (APHA), the American Water Works Association (AWWA), and the Water Environment Federation (WEF).
These organizations may be contacted by phone for more information on Standard Methods Online:
APHA: (301) 893-1894
AWWA: (800) 926-7337, (1-303-794-7711, outside U.S. / Canada)
WEF: (800) 666-0206 (1-703-684-2452 outside U.S. / Canada)
Citation: Standard Methods Online
 
Brief Method
Summary:
 Select sample volume that will allow color change to occur with the 15 mL addition of 0.01M EDTA titrant to the sample. Complete titration within 5 minutes. Dilute 25 mL of the sample to 50 mL. Add 1-2 mL of NH4Cl-NH4OH to get the pH to 10 or 10.1. Add 1-2 drops of Eriochrome Black T or Calmagite. Slowly add 0.01M EDTA titrant and stir, until end solution is blue. For samples with low hardness, use a 100 to 1000 mL sample for titration, and proportionately larger amounts of reagents.
Scope And
Application:
 This method is applicable to all waters. Polluted waters and wastewater samples must be pretreated. See abstract in Method 3030.
Applicable
Conc Range:
 Method is suitable for all concentration levels.
Interferences: (1) A number of metal ions may cause fading or indistinct end points (Standard Methods 2340C provides a listing of interfering metals and their potential effects). (2) Suspended or colloidal organic matter can interfere with the endpoint.
QC Requirements: not included
Sample Handling: Collect 100 mL in glass or plastic container. Acidify samples to a pH < 2 with HNO3. Analyze within 6 months.
Max Holding Time:
 6 months
Sample Prep Met SM 3030
Relative Cost: Less than $50
URL to obtain ordering information for this method:
http://www.standardmethods.org/
4679
Page 1